[ovs-discuss] Strange value of openflow dpid

[Ben Pfaff]

On Fri, Oct 05, 2012 at 09:48:08AM +0200, Michael Steiger wrote:
> I am currently using a hardware switch which is running openvswitch 1.2.2
> 
> If I set a new openflow controller using ovs-vsctl set-controller the
> connection is instantly available.
> 
> What I am wondering though is the value of dpid.
> 
> The MAC address of the management interface of the switch is
> eth0      Link encap:Ethernet  HWaddr 04:7D:7B:68:7B:C7
> 
> But the dpid the controller (floodlight) receives is
> DPID[00:00:04:7d:7b:68:7b:c6]
> 
> The dpid is always exactly minus one of the MAC address.
> 
> The OpenFlow 1.0 specification says
> "The datapath_id field uniquely identies a datapath. The lower 48 bits
> are intended for the switch MAC address, while the top 16 bits are up to
> the implementer."

This isn't behavior that I would expect from Open vSwitch.  I think
you'll have to ask your switch vendor.